My two take-aways from these two chapters are a) I should re-read Runge’s “Discourse Grammar,” and b) I'd like to learn more about "boundary features" in Levinsohn's "Discourse Features" book. Are there other works similar to these?

A footnote in Chapter 8 refers to an article by Levinsohn, “The relevance of Greek discourse studies to exegesis”http://www.sil.org/resources/publications/entry/40248
I think many of the points made in that article would have been a good way to bolster the over-arching case in Campbell’s book that linguistics have something to offer the student of the Bible.

I'll leave the content of chapter 7 on Halliday to the Hallidayans. Chapter 8 looks like two extended book reviews of Levinsohn and Runge with some critical comments. They do belong in an "Advances" book.